1. Field of the Invention
The present invention relates to a Josephson junction apparatus and a producing method thereof, more particularly, to a technique for producing a Josephson junction device onto a very thin functional polymeric film and for easily mounting it on irregular surface of shaped objects.
2. Description of the Related Art
Recently, a Josephson junction apparatus including a Josephson junction device have been studied and developed. The Josephson junction device is used as a switching element and a magnetic sensor. Namely, the Josephson junction device is not only used as a switching element having characteristics of high speed switching and a low power consumption, but also the Josephson junction device is used as a magnetic sensor having characteristics of an extremely high magnetic sensitivity. Note, a Josephson integrated circuit (apparatus), which comprises Josephson junction devices and wirings, is provided as a logic circuit or a memory circuit by using the characteristics of the Josephson junction device as a switching element. Further, in recent years, a superconducting quantum interference device (SQUID) and a superconductor-insulatorsuperconductor (SIS) mixer, which are examples of the integrated Josephson junction apparatuses, have been studied and developed by using the characteristics of the Josephson junction device as a magnetic sensor. Note, the SQUID can detect a very weak magnetic field and has a characteristic of high speed response, and thus the SQUID is often used in a medical apparatus for detecting biomagnetism, and the like. Further, the SIS mixer can be also used as an electromagnetic wave receiver through space for radio astronomical observations.
In the related art, the Josephson junction apparatus is formed on a hard substrate such a silicon substrate or a quartz crystal substrate, so that the Josephson junction apparatus cannot be easily mounted on an irregularly shaped surface, i.e., a curved surface, and the like.
Furthermore, in the related art, when forming the Josephson junction device onto a functional polymeric film, a wetting of the functional polymeric film occurs, which is caused by water or organic solvents being used repeatedly during the manufacturing process, and a dimensional stability of the film is decreased. Consequently, a minute Josephson junction (Josephson junction device) cannot be formed onto the functional film without causing a dimensional discrepancy of a pattern, and the reliability thereof is accordingly decreased.